The Cambridge Grammar of the English Language (Page 429) says:
Yesterday, today, tonight, and tomorrow are not traditionally analysed as pronouns, but belong in this subclass of nouns by virtue of their inability to take determiners. Compare, for example, Today/*The today is my birthday. They are also semantically like the central pronouns I and you in that they are characteristically used deictically. Unlike the temporal prepositions now and then, the pronouns have genitive forms: today’s, etc.
Expressions like last night and last/next week act just like yesterday, today, tonight, and tomorrow: They cannot take determiners without changing the meaning; they are characteristically used deictically; and they have genitive forms (last night's, etc.)
Although last night and last/next week are made up of two words, some pronouns such as reciprocal pronouns (each other, one another) are also two-word expressions, so being made up of two words shouldn't stop them from being pronouns.
In the determinative section, though, CGEL also mentions in a foodnote (Page 356):
We might also include [in the determinative category] last and next as used in temporal deictic expressions such as last week, next year, etc., where they contrast with the central determinative this.
But it's not clear how CGEL would analyze last night and last/next week.
Question 1
Would CGEL analyze last night and last/next week as pronouns or a combination of 'determiner (last, next, etc) + common noun (night, week, etc)'?
Question 2
If CGEL adopts the 'determiner + common noun' approach for last night and last/next week, why doesn't CGEL adopt the 'determiner + common noun' approach for yesterday, today, tonight, and tomorrow (with yester-/to- being a determiner and -day/night/morrow being a common noun)?