Follow these steps if you are using Word 2010 or a later version: If this is the setting that was already made, then the next thing to check is where the object is anchored. Select the block arrow, display the Shape Format tab of the ribbon, click the down-arrow at the right of the Send Backward tool (in the Arrange group), then choose Send Behind Text. The first thing to check, of course, is that the wrapping style didn't somehow get inadvertently changed. When Deborah would try to nudge the arrow into position, the text would jump around, even after setting the Wrapping Style for the object to Behind Text.
Deborah had some problems with a drawing object (a block arrow) placed behind the text of a table with rows of fixed width.