A cleft sentence has a corresponding non-cleft sentence, as in:
It was Tom that invented this. [cleft]
Tom invented this. [non-cleft]
A Comprehensive Grammar of the English Language (Quirk et al.) presents this cleft sentence where the personal pronoun he is the subject instead of it:
(1) He was a real genius that invented this. [cleft?]
In the intended reading, a real genius that invented this does not form a noun phrase. Assuming this, is (1) really a cleft sentence? If it is, what’s the corresponding non-cleft?
Note that he is being used referentially.