Reduce watering now then cut your potted loelia to ground level after it has flowered. Your compost should be nicely moist but 'under' rather than 'overwet' if you see what I mean.
Over winter in a shed or carport. (Lobelia can be killed off very easily if left too wet).
Then around early late March/April empty pot and divide your plants between other pots adding new compost that will encourage new growth and away you go!