Can 'when' and 'where' be used as relative pronouns?

The Words 'when' and 'where' are considered adverbs, which can introduce a question or an adverbial clause. For example:

When does he call? (the adverb 'when' is modifying the verb 'does call')

He calls when he can. (the adverb 'when' introduces the adverbial clause that modifies the verb 'calls')

The interrogative and relative pronouns take the place of a noun antecedent. For example:

Who gave you the flowers? (the pronoun 'who' takes the place of the noun that is the answer to the question)

My sister who has a garden gave me the flowers. (the pronoun 'who' and the relative clause refer to the noun antecedent 'sister')

The Words 'when' and 'where' also function as conjunctions. For example:

We went to the beach on Sunday where I got a really bad sunburn.