Following the advice in this question on travelling from Lille to Kortrijk / Courtray and onwards, on Saturday I headed over to Belgium. Coming back, I discovered that while there are trains quite late from elsewhere in Belgium to Kortrijk, the last train from Kortrijk or Mouscron to Lille is around 9.30pm.
If you miss the last train from Kortrijk to Lille (as I almost did due to a late running train to Kortrijk...), you can still get closer to the border to Mouscron for some time later. The last metro or the last tram from Tourcoing is quite a bit later than the last train, ditto from Roubaix (though that's further from Kortrijk or Mouscron)
Are there any ways to get a bus back from Kortrijk or Mouscron after the last train, to meet up with Lille public transport? Or is your only option the 4km walk from Mouscron to the Bourgogne metro station?