These commas surely must be superflous — if not considered an error.

The first seems wrong.

The second is OK in my opinion.

My take on your questions is this. # 1 as written, the comma looks and sounds superfluous. However, because "when " is conjunctive in nature, we can sometimes invert the clauses with a comma being correctly used: When he looked out from the hill in the morning, he could not remember having seen any sign of these in the valley,
# 2, stylistically and semantically, speaking, doesn't work for m

grammarfreakA slope is usually thought of as gradual.

"steep slope" is fine.

grammarfreakSecondly the past perfect construction in the main clause seemed odd being used together with a "when clause",

The use of the past perfect is also OK.

By the way, I don't think my original reply, as it appears now, is actua

However, because "when " is conjunctive in nature, we can sometimes invert the clauses with a comma being correctly used: When he looked out from the hill in the morning, he could not remember having seen any sign of these in the valley.

Sure, but this isn't the case because we have here an independent clause followed by dependent; as opposed to your example, whe

GPY"steep slope" is fine.

I know it is fine but a bit contradicting. I didn't say it was wrong but it seemed unnatural to me. I just want to clarify something. When I looked at these sentences which sometimes are awkwardly written but not grammatically wrong, I usually go by how it sounds to the ears. There may be a difference between yours and mine as we are

With a clause inversion, no comma is needed: I forgot my wallet this morning when I left the house in a hurry.

Yes, exactly. So why did the author use a comma there

grammarfreakI know it is fine but a bit contradicting. I didn't say it was wrong but it seemed unnatural to me. I just want to clarify something. When I looked at these sentences which sometimes are awkwardly written but not grammatically wrong, I usually go by how it sounds to the ears. There may be a difference between yours and mine as we are Atlantic apart.

After further review I must agree with you, GPY. The second sentence indeed seems okay: because ***'s sudden stopping was not the cause of the first clause, only an add on. I still think, however, that the author should have punctuate it differently though.

It may be helpful to note that "at which point" can be substituted for "when" in the second sentence but not the first, illustrating the different roles of the word in the two sentences.

Daithy However, because "when " is conjunctive in nature, we can sometimes invert the clauses with a comma being correctly used: When he looked out from the hill in the morning, he could not remember having seen any sign of these in the valley.Sure, but this isn't the case because we have here an independent clause followed by dependent;