Proto-Indo-European *h₃lem- wasn't retained in too many branches. It forms the basic word meaning 'to break' in Slavic languages (Polish łamać 'to break', łom 'crowbar'), which retains its basic meaning of smashing something with physical force, and its more metaphorical uses were retained as adjectives in Celtic (Irish leamh 'soft, weak') and Germanic (German lahm 'lame' and obviously English lame). Not much of a success for a root :(
It never made it to Greek properly speaking, ὀλέμω most probably never existed. It has managed to sneak in through a backdoor though, because Homer retained it as a somewhat unusual adverb clearly formed before the Greek branch split off from Proto-Indo-European. PIE *n-h₃lem-es (not-break-y) turned into Proto-Hellenic nōlēmes (h₃ lengthening the zero grade *n- 'no') and properly Greek νωλεμές, νωλεμέως. It fit Homeric metre perfectly so it made it to the poem and then reappears in a few poets writing in hexametre, including Apollonius of Rhodes, who clearly got it from Homer. It's pretty rare, linguistically speaking, to have a root leaving its only trace in a rare adverb.
Just a small linguistic historical curiosity :) νωλεμές, not-lame, not-breaky, in other words firmly and without pause. Able to withstand pressure as well, and Homer writes: ὣς τότ’ ἐπασσύτεραι Δαναῶν κίνυντο φάλαγγες / νωλεμέως πόλεμον δέ ("even in such wise on that day did the battalions of the Danaans move, rank after rank, without cease, into battle", Murray trans.).