has/ have elapsed

This may be a really stupid question, but why does "10 seconds has elapsed since..." sound right to me?
Surely it should be "have elapsed" for plural?
I can't think of another example where a has/have mix-up sounds okay.
Perhaps it's just my particular rural British vernacular

 

Ellipsis, I suspect. Our minds convert it to "[An interval of] ten seconds has elapsed since ..."

 

sounds logical, dig!... when i say it aloud with 'has' that's how it 'feels'... but i'd more likely say/write it with 'have'...

but why have anything between 'seconds' and 'elapsed' in the first place?

why not simply 'ten seconds elapsed' or some other wording that won't require either 'has' or 'have'?

 

Maybe had ?

My thought is the full sentence would be ''ten seconds of time has elapsed since ...'' You've take the of time out for flow, but the has remains.

OR

''ten seconds, had elapsed since ...'' May also work depending on the context.

 

That gives me problems with aspect. "Ten seconds elapsed" completed in the past, but adding "since" means we need an aspect that can be completing now. The past perfect gives us the required succession of events where the simple past doesn't.