Authorities are investigating the death of an elderly man who was found floating in a lake in Raymond. The Cumberland County Sheriff’s Department said William Prouty, 87, of New Hartford, Conn., was found by his wife around 9:25 a.m. Thursday. The family owns a seasonal home on a small island in the lake. Officials said Prouty had left the island to meet a maintenance worker on the mainland. The death is not considered suspicious. The cause and manner of death will be determined by the medical examiner’s office.