Britain’s Queen Elizabeth II was hospitalized Sunday over an apparent stomach infection that has ailed her for days, a rare instance of ill health sidelining the long-reigning monarch. Elizabeth will have to cancel a visit to Rome and other engagements as she recovers, and outside experts said she may have to be rehydrated intravenously. Buckingham Palace said the 86-year-old queen had experienced symptoms of gastroenteritis and was being examined at London’s King Edward VII Hospital. … Elizabeth has ruled since 1952 and is Britain’s second-longest-serving monarch, beaten only by Queen Victoria in terms of the number of years spent on...