++ Thanks beech, that answers my question and resolves the issue.

The table showing different behaviours was particularly helpful. It would appear that I have mostly been using OSes that do parse all arguments separately; for instance, I've had Mac OS X at home for the last eight years and that's what I would have used, almost exclusively, for scripts I've posted on this site. I was quite unaware that wasn't the normal case: hence my surprise at the behaviour on this borrowed laptop.