When the artist came home from LA, it seemed like a retirement. But it heralded an astonishing new chapter. Our critic remembers their thrilling dinners together – and the dazzling new works that arrived in his inbox every morning It was springtime in Paris and I was floating among young green leaves and white blossom – but I was not in a park. I was on an upper floor of the Fondation Louis Vuitton delighting, wallowing in several of David Hockney’s iPad paintings of his garden in Normandy. In o