Select the order.
Little did he know that his girlfriend was going to propose at the top of the tower that evening.
Little did he know that his girlfriend was going to propose at the top of the tower that evening.
Sentences starting with little take inverted word order, where the first verb comes before the subject (Little did he know). The dependent clause takes normal word order Subject/Verb/ObjectPlace/ObjectTime: his girlfriend/ was going to propose/at the top of the tower/that evening.