Answer:
There aren't any italicized noun clauses.
Explanation:
However, it is possible to explain something:
The subject is the doer of the action, in this case, <u>a lecture</u>.
The direct object is directly affected by the main verb, <u>what the children.</u>
The predicate noun is a noun or a phrase noun that renames the subject of a sentence after to be in any of its forms (present, past, participle), <u>what the children wanted to hear</u>.
The object of preposition is the noun or pronoun ruled by a preposition, <u>cleanliness</u>.