The main rulebook FAQ includes magical vortex spells now as one of the things LOS can be taken against. This:
Q: Does the ‘Look Out Sir’ special rule apply against all spells that
use templates? (p93)
A: Yes
And this:
Page 93 – Champions and Shooting
Change the third paragraph to “The only exceptions to this are
attacks that use a template (such as cannons, stone throwers,
breath weapons, magical vortexes and so on).”
Dwellers, on the other hand, doesn't use a template, and I can't find anything that indicates LOS can be used. Which is very unfortunate, if you ask me. Way to go if your house rules allow it.