Astrid Varnay, the Swedish-born American soprano who died on Monday aged 88, earned an international reputation as a Wagnerian singer of great dramatic power after what must rank as one of the most daunting professional debuts in operatic history.Her scheduled debut was to have been Elsa in in a Metropolitan Opera production of Lohengrin in 1942. But on the morning of December 6 1941, the day before the attacks on Pearl Harbor, Astrid Varnay was given a few hours notice by the Met to fill in for an indisposed Lotte Lehmann as Sieglinde for a matinée performance of Die Walküre.Although...