Hans Werner Henze has written twenty-one operas, an absurd feat of creative drive and stamina that hasn’t been matched since Verdi. Opera aficionados will go back and forth on which is his most fully realized and greatest work, and as with all arguments of that nature probably wind up right back at the same conclusions they began with. But it’s probably worth it, if you’re an opera fan, to check out as many of Henze’s creations as you can, and anyone in or around Philly has a great chance to give a listen to one of Henze’s most acclaimed – and least-heard – works beginning tomorrow night at the Perelman Theater, where a collaboration between the Curtis Institute, the Opera Company of Phladelphia and the Kimmel Center will debut Henze’s 1961 opera Elegy for Young Lovers. (David Patrick Stearns, Philadelphia Inquirer)