Filter names that begin with certain letter

I have a list of names that I need to apply an autofilter to that will let me filter all names that start with A-K and L-Z. I tried this but it does not work; it doesn't give an error but returns no rows:

If Sheet1.Fvalue.Value = "A-K" Then
        Sheet1.Range("D6:D" & endoffile).AutoFilter _
          Field:=1, _
          Criteria1:=Array("=A*", "=B*", "=C*", "=D*", "=E*", "=F*", "=G*", "=H*", "=I*", "=J*", "=K*"), Operator:=xlFilterValues, _
          Criteria2:="=", _
          visibledropdown:=False
      ElseIf Sheet1.Fvalue.Value = "L-Z" Then
        Sheet1.Range("D6:D" & endoffile).AutoFilter _
          Field:=1, _
          Criteria1:=Array("=L*", "=M*", "=N*", "=O*", "=P*", "=Q*", "=R*", "=S*", "=T*", "=U*", "=V*", "=W*", "=X*", "=Y*", "=Z*"), Operator:=xlFilterValues, _
          Criteria2:="=", _
          visibledropdown:=False
      End If