A Lost Romance is a quest in Fable III. Around three days after completing the Kidnapped quest (if you chose Elise/Elliot to live in the start of the game), you are able to get back Elise/Elliot if you told them to dump Laszlo/Linda. If you let them stay together, then the quest will not happen. Note that to start this quest you must have the Family Pack unlocked on the Road to Rule. You can either fast travel or run to meet Elise/Elliot outside the Orphanage where she/he will imply that you should propose. If you already have a ring then you can propose to them right there; if you don't they will say that you need one and the quest line will remain active until you propose "properly".