Sub Test()
Dim Plage As Range, c As Range
Dim I As Long, Ligne_Debut As Long
Set Plage = Cells(19, 1).EntireRow
If Application.WorksheetFunction.CountA(Plage) <> 0 Then
Ligne_Debut = 21
Else
Ligne_Debut = 20
End If
For I = Ligne_Debut To 39
Set c = Rows(I).Find("*", , xlValues, , 1, 1, 0)
If c Is Nothing Then Rows(I).Hidden = True
Next I
Set Plage = Nothing
End Sub