When I was growing up in Italy, it was a nearly a mandate for well-heeled northerners to summer on the sun-warmed lakes at the foot of the Alps. Boats would dock at island gardens, people took slow promenades along the shore followed by a leisurely Sunday meal on the leafy veranda of, say, Albergo Verbano, where Arturo Toscanini, George Bernard Shaw and Ernest Hemingway, to name notable guests, once stayed.