To allude to something means to make an indirect reference. (Don't use allude to mean "to refer directly.") To elude means to evade or to escape understanding or attention. See also: Allusion and Illusion.
Examples:
Some passages in the New testament allude to incidents and prophecies in the Old Testament. The meaning of this particular passage eludes me.
Practice:
(a) In last night's speech, Bill Clinton _____ to Barack Obama without ever mentioning the president by name.
(b) Basketball fans were amazed that the blatant foul had somehow ____ the referee.
