Syllabifying S into an onset?

Question

Someone recently called my attention to a hexameter by Lucilius:

Jānus, Quirīnus "pater" siet ac dicātur ad ūnum.
Janus or Quirinus may be "father"; every single [god] is called this.

And there's something a bit odd about this scansion. The second syllable of Jānus has to scan as light, even though it's followed by another consonant. In other words, the final -s before a stop isn't treated as a coda.

This makes sense to me—phonologically, squ- is a valid syllable onset, as in squālor. But I've never seen this sort of syllabification in metered poetry before: normally, s between a vowel and a consonant is treated as a coda (e.g. -us la- in Aeneid I.2).

How common is this? Does it happen in Classical authors too (or really anyone except Lucilius)? And is there a name for it?

Answer 1

The standard analysis of this phenomenon, which shows up in Early or Old Latin poets such as Lucilius and Plautus, is that word-final s was not resyllabified, but rather prone to elision when followed by a consonant (but not when followed by a vowel). The light scansion of a word-final sequence of short vowel + s (usually excluding words where the s was historically derived from a geminate) can occur regardless of whether the s can form a valid onset cluster with the following consonant(s).

Some sources discussing this describe the condition for elision more specifically as "word-final s after a short vowel", but I don't see how we'd know whether it did or didn't also occur after a long vowel, since elision in that context wouldn't affect the meter.