I don't think the differentiation you're talking about actually happened until after TSR had been sued (at least insofar as printed material is concerned). Although that's largely because the earliest rulebooks give almost no details on what D&D's orcs looked like.
The point I was making was that Gygax's orcs were never infringing. It was more like, "Hm, Tolkien used orc ("ogre") to mean a bestial humanoid, I can do that, too." I assume it's the Gygaxian sense of humor that led to the orcs being described as pig-like; although Tolkien's orcs were broad-nosed, they were not pig-like. Orc, of course, is an unrelated British word meaning pig or boar.
So to reiterate, as this point seems to have been missed; Tolkien did not invent the word orc, it is a cognate of ogre, and those words all come from a word for demon, orc or ork, which comes from the Latin Orcus. Tolkien believed that orc ("demon") was probably inadvertently confused with an Old English word of a similar sound meaning "monster," but Wikipedia says he was almost certainly mistaken.
Orcus -> orc
It's kind of like sherbet/sorbet. Other D&D isms include:
drow - derro - druagh - duergar
These are all the same word, referring to subterranean dwarves or fairies.
treant - ettin - jotun
Treant is an invented to satisfy the Tolkien estate's claim on
ent. Ent and ettin are, of course, both cognates of jotun. All mean "giant."
Bahamut - behemoth
Bahamut and behemoth are the same word, transliterated in two different ways.
dragon - drake
Yup, those are the same word.