Today: two lessons in how to wear a hat. My exemplars are the painter L S Lowry and the singer-songwriter Leonard Cohen. Dr Johnson said of the metaphysical poets that in them “the most heterogeneous ideas are yoked by violence together”. We don’t hold with violence in this column, nor do we mean to court the cheap controversy of heterogeneity. Lowry and Cohen might, on the face of it, make strange bedfellows, but both took London by storm last week – Cohen at the O2 Arena, Lowry at Tate Britain – and both define themselves by the way they wear a hat.