In a fragment from Tolkien's incomplete revisions to The Lay of Leithan, the following appears:
Southward he turned, and south away/his long and lonely journey lay,/while ever loomed before his path/the dreadful peaks of Gorgorath.
Beren and Lúthien p. 272 (American edition)
This passage is about Beren eventually abandoning the land of his home and going south.
Is Gorgorath as an alternative for Gorgoroth used anywhere else? It seems odd that Tolkien would change the name in only one instance just so it would rhyme with path.
I do not have access to any HoME books, and I only have this in Beren and Lúthien, so is information about Gorgorath found in those books?