I would have said 'non' always requires a hyphen. But there are a lot of people who don't like hyphens, it could be a new spelling trend.

There are words, of course, where the 'non' is an essential part of the word, such as "nonchalance" - then it is written together.

Danke für die Antwort! Habe jetzt gesehen, dass in einigen Einträgen in LEO die Variante ohne Bindestrich als amerikanisch, die mit als britisch angegeben ist, z.B. non-combatant, non-commercial, non-committal, non-competitive, ...
(Die fangen alle mit c an???) Ist das denn so?

I looked this up a while ago and my memory is that yes, the hyphenated spelling is chiefly BE. AE doesn't usually hyphenate most prefixes unless it would be unclear or hard to read if they weren't hyphenated (as perhaps with non-native).

There might be a discussion somewhere in the archive (Suche in allen Foren) with more examples of BE/AE prefix differences, from the Chicago Manual of Style, but I can't think what it might have been titled.

ne ist nicht so...non smoker