As he’s worked with collaborators as diverse as Dizzee Rascal and Kylie, the euphoric eclecticism of Calvin Harris’ second record makes sense. And it certainly shapes the looped mariachi of “Relax” or, say, P-Funk workout “Yeah Yeah Yeah La La La”. But the triumph of Ready for the Weekend—which has slow-flickering clarion call “I Am Not Alone” at its centre—is the Scotsman’s emergence as both the architect and conduit of arena-sized pop moments.