Modify my copy from one cell to another macro

So, I got some code from the great people at this forum, and was wondering if it could be tweaked a bit.
The coded copies txt from one field to another, and puts itself at the top of the cell and removes the txt from the previous cell.
The problem is, if cells in the column are blank it has started to put a square symbol in, so when we autofilter it will show squares. I can work around it by filtering for the squares and deleting them manual which is still a time saver. The problem is if the squares get put in between other txt there's no way to delete them. I can live with it, but figured it would be worth asking, as it did not always do this.

Thanks in advance

Sub AJ2AI()
    Dim cell As Range
    Dim s As String
    Dim r As Range
    Dim sFrom As String
    Dim sTo As String
    Dim lFrom As Long
    Dim lOffset As Long
    Dim rRange As Range
    Dim rTop As Range
    Dim rBottom As Range
    Dim sh As Worksheet

    sFrom = "AJ"
    sTo = "AI"

    On Error GoTo EF
    Application.EnableEvents = False

    lFrom = Range(sFrom & 1).Column
    lOffset = Range(sTo & 1).Column - lFrom

    Set sh = ActiveSheet
    With sh
        Set rTop = .Cells(2, lFrom)
        Set rBottom = rTop.Offset(.UsedRange.Rows.Count - 1)
        Set rRange = Range(rTop, rBottom)
    End With

    For Each cell In rRange
        With cell
            Set r = .Offset(0, lOffset)
            s = r.Value
            If InStr(s, .Value) = 0 Then
                s = .Value & vbLf & s
                With r
                    .Value = s
                    .VerticalAlignment = xlTop
                End With
                .Value = ""        'remove this line if you want column(sFrom) to remain as is.
            End If
        End With
    Next cell

EF:
    Application.EnableEvents = True
End Sub

Replace the line

s = .Value & vbLf & s

with

If (s <> "") Then
   s = .Value & vbLf & s
Else
  s = .Value
End If

The square is the present of a nonprintable character. If you want the concatenated text to appear on different lines within the cell, you will have to put up with it on the autofilter. You could use a different delimiter, like "|", but then the text would all appear on the same line.