Are adverbials part of a subordinate clause?

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hello,

“…when we arrived” in Sara Throne’s Mastering Advanced English Language Second Edition is given as the subordinating clause in “…when we arrived at the new house”. Shouldn’t it be the whole thing? Why, if main clauses can have adverbials, cannot subordinating ones?

2

Yes, the whole thing is the subordinate clause. (Not ‘subordinating’ clause, though ‘when’ is the ‘subordinating conjunction’.)