A verb glossed {“curl (tr.), braid hair, tie” >>} “curl (intr.), bend (intr.), wind (twine round anything), twine” in the Gnomish Lexicon of the 1910s (GL/54), clearly based on the early root ᴱ√LOKO “twine, twist, curl” (QL/55). Tolkien probably decided this verb was intransitive while introducing G. loctha- “curl (tr.), bend, wind, twine, tie knot, tangle” immediately below it.
Neo-Sindarin: I adapt G. loctha- as ᴺS. loetha- “to curl, bend, wind, twine” to better fit Sindarin phonology, and I would use it both transitively and intransitively, because I prefer to use ᴺS. log- to mean “haul, drag, pull, draw”.
A noun appearing as G. lonc “curl” in the Gnomish Lexicon of the 1910s (GL/54), clearly based on the early root ᴱ√LOKO “twine, twist, curl” (QL/55).
Neo-Sindarin: Since the later meaning of the root √LOK “bend, loop” is fairly close to its early meaning, I would retain ᴺS. lonc “curl” for purposes of Neo-Sindarin; compare Q. lócë “bight, bend, curl of hair”, a later word of similar meaning (PE17/160).