Set the Sort: to Capture time. It is more than likely now set to Added Order. Which if the import dialog isn't set to Capture Time LR will display imported images in the order LR imported them.
There are multiple places to set the sort order, and none of them interact with the others.
In the Import dialog: Set the sort order to view your images how you want. Note that this ordering is only for viewing in the dialog. You have no control over the order in which the images are actually imported. The import sequence number can be used in the Library module to see what order the import was done, but it has no useful purpose other than to confuse people. However, the file number created by the camera can be of great importance.
In the Library grid: Set the sort order to view your images how you want. By capture date or file name are the most common.
I rename my files to yyyymmdd_nnnn while transferring them from the card to the hard drive, so the capture date and file name sorting are the same for me. I am also guaranteed unique file names.
OS X El Capitan 10.11.6
Did you change the sort order as described above?
Changing the sort order to Capture Time should display images based on the time you captured them.