On turning eighty, David Hockney sought out rustic tranquility for the first time: a place to watch the sunset and the change of the seasons; a place to keep the madness of the world at bay. So when Covid-19 and lockdown struck, it made little difference to life at La Grande Cour, the centuries-old Normandy farmhouse where Hockney set up a studio a year earlier, in time to paint the arrival of spring. In fact, he relished the enforced isolation...