LONDON—Wrapped up in coats and with London’s famed landmarks behind them, members of the Royal Opera Chorus sing the Anvil Chorus from Giuseppe Verdi’s 1853 opera “Il Trovatore” in their first reunion in a year. Standing apart due to social distancing measures brought about by the COVID-19 pandemic, the 25 singers are gathered on the rooftop of the Royal Opera House in London’s Covent Garden. Their performance, which also includes the final chorus from Wolfgang Amadeus Mozart’s “The Magic Flute”, will be streamed on the Royal Opera House’s Facebook page on Good Friday as the venue prepares to welcome back audiences in May. “It’s about greeting Easter time and greeting the world after lockdown,” American conductor William Spaulding, who is the chorus director of the Royal Opera House, told Reuters. “We all need a bit of hope right now … it’s been such a rough year and in particular for …