How do we arrange to attend an evening concert at Our Lady of the Rocks?
Are you with a cruise ship or traveling to Montenegro for few days?
The best way it will be to contact many of their agencies online and book through them. Most of them will have that offer.
If you are on a cruise ship, the chances of the ship staying till the evening are small, since they usually leave around 5pm. If your ship is staying till late, they may have an organized tour for the concerts.