From the introduction: "Does it make any difference whether an adverbial clause like when the wolf arrived precedes the main verb ore follows it? For example, do (1a) and (1b) (which allude to the tale of "The Three Little Pigs") mean the same? And what about the same sentence with the subordination reversed, as in (1c,d)?
"(1) a. When the wolf arrived, he was picking apples. b. He was picking apples when the wolf arrived. c. When/While he was picking apples, the wolf arrived. d. The wolf arrived when/while he was picking apples.
"The great British linguist J. R. Firth always maintained that when there is choice, there is meaning. The purpose of this paper is to explain some of the differences that are made to the meaning of a passage by preposing versus postposing adverbial expressions such as those which appear in (1)."
Levinsohn, Stephen H.
"Preposed and postposed adverbials in English,"
Work Papers of the Summer Institute of Linguistics, University of North Dakota Session: Vol. 36, Article 2.
Available at: https://commons.und.edu/sil-work-papers/vol36/iss1/2