In my experience, you need to go really fast with offense when using lockdown or 1/4 guard in the gi. Basically, get that lockdown, rotate your body and get the electric underhooks FAST.
Once they have a hold of that collar and are threatening a choke, it has to be respected. With an over under clinch, squaring up to your opponent and stretching that lockdown fully downward (to pull your opponent lower down your body), you're pretty much safe from collar chokes. Note: DO NOT go for double unders if your opponent has one hand sunk in deep for the collar choke - you'll end up with no hands to defend your neck with the other hand comes around.
So - if there's a threat of a collar choke, stay safe by squaring up and utilising an over under (which your opponent will happily take), then once the threat is gone, work to get to either dogfight or electric underhooks FAST. Also, keep your head GLUED to your opponent's body at all times - that eliminates all lapel choke possibilities.
That's my experience with it anyway, I'm sure there's loads more that I haven't seen/felt/experienced yet!