The Collaborative International Dictionary of English v.0.48:

Elucidative \E*lu"ci*da`tive\, a.
   Making clear; tending to elucidate; as, an elucidative note.
   [1913 Webster]

WordNet (r) 3.0 (2006):

elucidative
    adj 1: that makes clear; "a clarifying example" [syn:
           clarifying, elucidative]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "elucidative":
   allegorizing, annotative, clarifying, critical, demonstrative,
   demythologizing, editorial, enlightening, euhemeristic, exegetic,
   exemplificative, explaining, explanatory, explicative, explicatory,
   expositive, expository, glossarial, illuminating, illuminative,
   illustrative, rationalistic, rationalizing, scholiastic