If we break it down and rearrange it, Owner-of-heaven; Oní-Ọ̀run. It is elision of words in Oní-Ọ̀run makes it Ọlọ́run.
Ká dà á sílẹ̀ kí a tún un ṣà, O-Ní-Ọ̀-Run; Oní-Ọ̀run. Ìpàrójẹ tó dé bá Oní-Ọ̀run ni ó fi di Ọlọ́run.