Particle emission begins from the frame I start rendering from, not the frame it should begin from? I'm trying to render a simple animation of the camera circling a lit candle, with particle emission beginning at frame -100 so it's lit before frame 1.

To speed things up I'm rendering to pngs across multiple computers. For example I've set things up to render from frame 1, frame 20, frame 40, and frame 60 on four PCs. However the first few frames on each computer seem to show emission starting again, i.e. frames 20, 40, and 60 show no particles. 

How can I fix this so I can collate all my files at the end for one smooth flame animation? Is this a known issue?

Any advice or tips for a novice would be great!
So I've discovered what causes this. When you're animated from a frame that isn't frame 1, in the timeline you have to make sure you're current time point is on frame 1. If you have the frame you're rendering from as your time point then it begins particle emission from that frame hence a few frames of no emission.