When `until last Easter' serves as an adverb it is an exocentric construction.    From Wordnet, Princeton University. 

Broccoli would first meet the exocentric billionaire, Howard Hughes, who was financing the picture.    From Wordnik.com.  [MI6 :: 007 News] Reference

Diachronic versus synchronic approaches vied with endocentric versus exocentric to confound the neophyte.    From Wordnik.com.  [VERBATIM: The Language Quarterly Vol III No 2] Reference

Fn1. e.g. here - the transition from egocentric to exocentric in population sense as display shrinks.    From Wordnik.com.  [July 2006] Reference