Update:
Haven't come across a solution so far, so in the meantime I've added a bit of code to exit the sub if the workbook name is changed:
Sub SplitView()
' vertically splits view
Dim wb1 As Workbook
Set wb1 = ThisWorkbook

If ActiveWindow.WindowState <> xlMaximized Then ' exits if window is not maximized
  Exit Sub
End If

If Not wb1.Name Like "Workbook1.xlsm" Then ' exits if book is renamed
Exit Sub
End If

 ActiveWindow.NewWindow
 Application.Windows.Arrange ArrangeStyle:=xlVertical, ActiveWorkbook:=True ' vertical view
 Windows("Workbook1:2").Activate ' activates window 2
 ThisWorkbook.Worksheets("Sheet1").Range("A15").Select
 ActiveWindow.FreezePanes = True ' freezes header
 ActiveWindow.Zoom = 87 ' resets view for split window
 Windows("Workbook1:1").Activate ' activates window 1
 ActiveWindow.Zoom = 87 ' resets view for split window
 ActiveWindow.SmallScroll ToRight:=16 ' scrolls right so second report is in view

End Sub
Hopefully a solution is possible, but if not, this way there won't be any errors.