“Philadelphia Orchestra associate conductors are like U.S. vice presidents: They have huge exposure, a bit of dirty work to do, and ascend to the boss’ job only in dire circumstances. Nonetheless, Philadelphia’s Cristian Macelaru (once associate conductor – new title, ‘conductor-in-residence’) is making a more-than-vice-presidential career for himself” – including important gigs filling in for the late Rafael Frühbeck de Burgos and the ailing Pierre Boulez.