[seszett]

That's when hyphenating a word, not between different words linked by hyphens.

[OJFord]

That's exactly what a hyphenated word is.

[monadgonad]

No. "Hyphenating a word" here means when a whole word is split by a hyphen to continue on the next line of a justified column of text. In that case only, a long s is used before the hyphen.