Lancelot is a name given to the suit of armor in the front hallway of Henri Dijon's mansion. It has several parts that can be oiled, including an axe that allegedly previously belonged to Anne Boleyn and Lizzie.
Oiling the axe is not recommended. Oiling the helmet is necessary to obtain an item and information needed to find the hidden treasure of the Crouton family on the Misty Acres estate.