The acknowledgments from Elric: The Sleeping Sorceress (Gollancz, 2013) state that this map was first published in Warlocks and Warriors, edited by Douglas Hill (Mayflower Books, 1971).
Those in Elric: The Sleeping Sorceress (Del Rey, 2008) state that it first appeared in Elric of Melniboné (Hutchinson, 1972), buy that credit is probably incorrect.
This map differs from the other maps of the same name first published in 1967 and 1972. This map has the title above the compass rose in the lower right if the map and is signed "J. Cawthorn" in the lower left corner outside the border.