A quirk with quark

Perhaps  was too quick to judge anyone else's linguistic skills.
The other day I encountered this from Stephen Hawking's A Brief History of Time:

The word quark is supposed to be pronounced to rhyme with quart, but with a k at the end instead of a t, but is usually pronounced to rhyme with lark.

Huh?  Let's take a better look at this, curtosy of http://lingorado.com/ipa/

British

quark	~kwɔːk~
quart	~kwɔːt~
lark	~lɑːk~

American

quark	~kwɑrk~
quart	~kwɔrt~
lark	~lɑrk~

Hawking apparently doesn't like American pronunciation.