JLA, Sam. usage is a Hebraism. (Note that in JLA it only occurs as a textual variant to אלו. Aramaic cognates are ˀlw conj., lˀ #2 adv., and the precative prefix l_ in Samalian and Fakh(112002).
Page refs. in other dictionaries: Tal Sam: 427bDNWSI: 567DISO: 136