لَوْلَا
1.
and لَوْمَا: see حَضَّهُ.
2.
لَوْلَا فَعَلْتُ كَذَا means Wherefore didst not thou such a thing? and لَوْلَا تَفْعَلُ كَذَا means Wherefore wilt not thou do such a thing? and in like manner, لَوْمَا and ألَّا and هَلَّا. See an example in the Qur'an, 10:98, explained in article إِلَّا.
3.
لَوْلَا هٰذَا لَكَانَ ذَاكَ
Had not this been, or but for this, that had been, or would have been.
4.
لَوْلَا is followed by a noun in the nom. case (as in the Qur'an, 8:69), or by a verb, as in exs. above.