As I scroll through my list of friends, my finger hovers over the mouse and I consider – for perhaps the second time this week – whether I ought to send my nan a message. While not a frequent Facebook flier, she decided a few years ago to have a “jolly good try” at getting online, and subsequently I received my first octogenarian-friend request: my 89-year-old nan now had a virtual as well as a physical presence.

So why not send her a note? The problem is that, in the harsh physical world, she no longer exists: last December, when she was 91, a stroke stole her from her four children, nine grandchildren and 10 great-grandchildren. But on Facebook and Skype, and the timeless world of comments and pictures, I can still find my grandmother and pretend – just for a moment – that she is still with me.

Of course, I realise that the probable outcome of typing a quick “Hi, how are you?” into the chat box would either be silence, or a bemused reply from my aunt. I know that she was laid to rest on 15 December 2015; that she had the kind of life that people refer to as a good innings. But that doesn’t stop me hoping that if I pressed send, she might answer one last time.

My nan wasn’t a regular part of my life in a traditional sense. She moved to Bath – a good three hours’ drive from where I lived in Bedfordshire – in 1989, when I was 11, and I probably saw her no more than once a year as a teen. But we often wrote to one another – arguably a more intimate method of correspondence than chatting on the phone – and when I moved to France in 2009, she regularly came to stay.

Getting to know your grandmother as an adult – seeing the world eye-to-eye – isn’t a gift afforded to many. The fact that my nan lived to 91, retaining her marbles and wicked sense of humour, meant that we formed a bond that transcended the normal grandma-grandchild relationship. A people person, she was always out-and-about, travelling and mingling; and this may be the reason why being with her was always so much fun.

It is probably also why, although I knew she had a heart problem and had had a series of mini-strokes over the preceding decade, I was still shocked when she was hospitalised in August last year. This was the woman who had broken her thigh bone and bounced back aged 83; the woman who had once had a mini-stroke and taken the bus home afterwards.

This time, too, with a strength of spirit common to her generation, she didn’t give up without a fight: after a few weeks she had regained enough speech to dictate an email for my aunt to send me. “Hopefully be out of here soon,” it said. “Hope to come and see you.”

No doubt she suffered in hospital and was frustrated or sad from time to time, but her quickness to smile and laugh despite her difficulties caused one of the nurses to joke that she was their favourite. My grandfather, to whom she had been married for 65 years, used to sing to her on his visits; something that sounds wonderfully old-fashioned and touchingly loving. Her children were with her each day. If love itself could have cured her, then she would still be here.

Sadly, my crossing from France was delayed because of passport problems, and shortly before I made the trip to Bournemouth hospital with my five children, including a new baby, and exhausted husband in tow, she had a second stroke. I was warned that she had regained very little of her speech; that she might not recognise me; that her vision wasn’t great, and I have to admit that, walking along the corridor to her room, I felt sick with nerves.

But although her weight had plummeted and I saw her with grey hair for the first time in my life, she was still my lovely nana. Our eyes locked and, while she was barely able to speak – bar the words “wow” and “ha!”, the reacquisition of which sums up her character perfectly – I could see through her expression that she was still very much there. She held my new baby’s hand and, as little Robbie gazed at this woman 91 years his senior, there was an almost breathtaking connection.

“I can see her pulling through,” I optimistically told my mother on the telephone.

A month later, the news arrived that she had passed away – at home, in her daughter’s arms: and it hit me for six. Longer term, though, I have not been sure how to grieve: the status of our relationship means that I haven’t yet felt the extent of her loss, but instead experience it in waves, when I pass a photograph or click on my Skype contacts and am reminded once again that she has gone.

Wynn Cross’s Facebook page.

In a way, Nan and I had always existed in a virtual world of sorts – snail mail, then Facebook rather than telephone or in person – so I am not reminded by an empty chair or tangible absence that she is no longer around. I haven’t – like my grandad – walked into the kitchen and seen her ghost.

True, the letters no longer arrive, but to all intents and purposes, life remains a sort of odd status quo. “The time seems to fly by much too quickly for my liking,” she wrote in the last letter I had from her; and during her final stay in France, in 2013, she told me she was living on borrowed time. Looking back, I wonder if she knew.

Death is, in so many ways, straightforward. There are rules: you have a funeral, you shed tears, buy flowers. But in this age of social media – where we are split into two selves – there remains a conundrum. What happens to our cyber-self when we pass? Pages of others who have died are often filled with post-death notes from friends: “I miss you” or “Still can’t believe you’re not with us”. Perhaps keeping our profile in existence is providing a much-needed outlet for others?

These days, families and friends are often scattered by circumstance: lured elsewhere by opportunity, lifestyle or the cost of living. Yet friendship is, more than ever, surviving long-distance; in this internet age, close connections can form with people whom we rarely – or never – see in the flesh.

In this way, we create an existence that transcends the physical. A ghost in the machine. My grandmother is here, yet she is gone; is present online, yet only in a virtual, cyber afterlife. I am comforted but haunted by her name in my friends list.

And still, once in a while, I consider messaging her, on the off chance that my greeting might just get through.