You can start with something like that:
Backup your files before test, test before use, use at your own
Code:
Sub test()
Dim MyPara As Paragraph
For Each MyPara In ActiveDocument.Paragraphs
If Left(MyPara.Range.Text, 6) = "Friday" Then
MyPara.Range.Font.Bold = True
MyPara.Range.ParagraphFormat.KeepWithNext = True
End If
Next
End Sub