A lock assembly for selectively and releasably holding a pivoting armrest of a vehicle in place relative to an adjacent seat back is disclosed. The lock assembly includes a first locking element fixedly attached to the seat back and a second locking element movably attached to the armrest. Both locking elements have engagement surfaces whereby the second locking element is releasably engageable with the first locking element. The first locking element includes a cover that, together with a base, defines a pocket. The second locking element includes a spring loaded attachment assembly. The assembly provides operator-movable attachment to the armrest. The second locking element further includes an engagement portion on which the engagement surface is formed and an anchoring portion. An operator-manipulable release tab extends from the engagement portion and through the tab-passing slot of the first locking element when the first and second locking elements are engaged.