The Once and Future King Book 3, Chapter 38
Even after the trial, Lancelot remains true to the Grail, and Guenever is very angry with him. Arthur organizes a tournament near Elaine's castle, and Guenever forbids Lancelot to go. When she sees she is driving him crazy, she relents and more kindly tells him to go. Of course, he must visit Elaine, since he has the news of their son Galahad finding the Grail and going to God. When he arrives, Elaine assumes he is staying for good.