Jonathan Cohen, founder and artistic director of the period ensemble Arcangelo, has said that, for him, the starting point for any performance project is the musicians rather than the music. His approach has been to assemble outstanding vocal soloists and individual top-flight musicians, all of whom share like-minded beliefs in music and perform it as a chamber consort, which was in fact, as Cohen says, the mode most music employed up to the early Beethoven. Arcangelo is now one of the most acclaimed ensembles in the world, and it’s not difficult to see why. Launching with a palpable verve and…