Change question order
From LimeSurvey Manual
Reorder questions by clicking on the Change Question Order icon in the group toolbar.
If you have a survey with more than one question in a group, the questions are displayed according to this question order. You can change this order by simply click on the 'Up' and 'Down'-buttons.
If you set conditions on question the particular condition might prevent re-ordering a question before/after another question. In that case you will have to delete/change that condition first.