I can't seem to work out if this is possible-- can you book tickets on Eurostar.com with a stopover?

What I want to do is book from London - Lyon, with about 5 or so hours in Lille (so I can visit here). Is this possible all in one booking, or should I just book London <-> Lille on eurostar.com, and Lille <-> Lyon on voyages-sncf?

As far as I can tell, there's not a massive price difference between booking them together or separately.

Thanks...