She knew the ex-army foreman of a factory in South Boston, and last saw him in a briefing room in Portland. At some point shortly before the Great War of October 23rd, 2077, she abruptly phoned the foreman and informed him of the impending global nuclear war, by speaking in code and pretending to tell him about her nephew's baseball team. The foreman then decided to send all of his worker's home to their families, and was saved when the bombs hit when he was sleeping in his chair. He believed he would have been vaporized by the blast had he been doing his regular thing when it occurred, and thanked Lavonne. Her fate is unknown.
Lavonne is only mentioned in Fallout 4.