إِنْ كَانَتْ كَلِمَةُ «كُلّ» دَاخِلَةً فِي حَيِّزِ النَّفْيِ
If the word kull itself falls within the scope of negation.
This is not restricted to a sentence-initial subject. Kull can relate to an agent, object, intensifier or another construction. When it is under negation, the question is whether total inclusion is denied or whether the predicate is denied for every individual.
One must therefore identify the actual operation of the negative particle on the verb, adjective or predicative relationship, not merely locate the word kull.