The displaced lām may appear before the predicate. If a prepositional predicate comes first, the lām may appear before the delayed noun of إِنَّ. The lām adds emphasis; the grammatical case still comes from the word's role.
Sentence
Noun of إِنَّ
Predicate of إِنَّ
Position of lām
إِنَّ الشِّرْكَ لَظُلْمٌ عَظِيمٌ
الشِّرْكَ
لَظُلْمٌ عَظِيمٌ
before the predicate
إِنَّ فِي ذَٰلِكَ لَآيَةً
لَآيَةً
فِي ذَٰلِكَ
before the delayed noun