I'm already doing that.

I posted the following in the winapi newsgroup.
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When I lock the Word app window with the code below, the lock does not hold
unless I put a breakpoint on, say, the With appWord statement following the
commented out Sleep statement.

Since it worked using a breakpoint, I ASSuMEd that I could use Sleep to
achieve the same effect. Well, I tried Sleep 20000 and that did no good.

What do I have to do to make sure the Lock works?
The code will evetually be part of a .exe or .dll, so cannot rely on manual
breakpoint.

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal
lpClassName As String, _
   ByVal lpWindowName As String) As Long
Private Declare Function LockWindowUpdate Lib "user32" (ByVal hwndLock As
Long) As Long

   Private Declare Function GetWindowText Lib "user32" _
       Alias "GetWindowTextA" _
       (ByVal hWnd As Long, _
        ByVal lpString As String, _
        ByVal cch As Long) As Long

   Private Declare Function GetActiveWindow Lib "user32" () As Long

   Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

Private Sub btnByeBye_Click()
   Unload Me
End Sub

Private Sub btnNoTemplate_Click()
   Dim appWord As Word.Application
   Dim docWord As Word.Document
   Dim lngHWnd As Long
   Dim lngReturn As Long
   Dim strCaption As String

   Set appWord = New Word.Application
   lngHWnd = FindWindow(vbNullString, "Microsoft Word")
   If lngHWnd = 0 Then
       Debug.Print "Not found"
       appWord.Quit
       Set appWord = Nothing
       Unload Me
       Exit Sub
   Else
       Debug.Print "Handle is" & Str(lngHWnd)
       Debug.Print "Caption is: " & ActiveWindowCaption(lngHWnd)
       lngReturn = LockWindowUpdate(lngHWnd)
       If lngReturn = 0 Then
           Debug.Print "Lock failed"
           appWord.Quit
           Set appWord = Nothing
           Unload Me
           Exit Sub
       Else
           Debug.Print "Lock success:" & Str(lngReturn) & Str(lngHWnd)
       End If
   End If

'    Sleep 1000
   With appWord
       .ScreenUpdating = False
       .Visible = False
       .WindowState = wdWindowStateMinimize

       ' Blob appears
       Set docWord = .Documents.Add(Visible:=False)
       With docWord
           ' Makes blob disappear
           .ActiveWindow.Visible = False
           ' Do stuff here
           .Close
       End With
       ' Blob appears, then goes away
       .Quit
   End With
   Set docWord = Nothing
   Set appWord = Nothing
End Sub

Private Function ActiveWindowCaption(Optional hWnd = -1) As String
   ' Return caption for active window.
   Dim strCaption As String
   Dim lngLen     As Long

   If hWnd = -1 Then
       hWnd = GetActiveWindow()
   End If

   strCaption = String$(255, vbNullChar)
   lngLen = Len(strCaption)

   If (GetWindowText(hWnd, strCaption, lngLen) > 0) Then
       ActiveWindowCaption = strCaption
   Else
       ActiveWindowCaption = ""
   End If
End Function

Ayup, that was the problem, except it was AutoExit, not AutoClose.