Remove XML sections where <MediaFileLink> tag does not contain http://

Pat Chown

In the example below only one of the <MediaFileLink> tags are a good URL. How can I completely delete the two bad ones?

<MediaFile>
  <MediaFileFormatCode>15</MediaFileFormatCode>
  <ImageResolution>1.3</ImageResolution>
  <MediaFileLinkTypeCode>23</MediaFileLinkTypeCode>
  <MediaFileLink>cm</MediaFileLink>
  <MediaFileDate>cm</MediaFileDate>
</MediaFile>
<MediaFile>
  <MediaFileFormatCode>03</MediaFileFormatCode>
  <MediaFileLinkTypeCode>01</MediaFileLinkTypeCode>
  <MediaFileLink>http://images.myfileurl.biz/1234567891822.jpg</MediaFileLink>
</MediaFile>
<MediaFile>
  <MediaFileTypeCode>04</MediaFileTypeCode>
  <MediaFileFormatCode>03</MediaFileFormatCode>
  <ImageResolution>96</ImageResolution>
  <MediaFileLinkTypeCode>06</MediaFileLinkTypeCode>
  <MediaFileLink>C:\Folder\sub1\sub2\COMP\sub3\ProprietaryProducts\1234567891822.jpg</MediaFileLink>
  <MediaFileDate>20170727</MediaFileDate>
</MediaFile>

I used this for blank ones ^\s*<MediaFile>\r\n^\s*<MediaFileLink>.?</MediaFileLink>\r\n^\s</MediaFile>