Insert a blank row ABOVE a certain character in a column when the character can repeat

Hi,

I am new, and have looked for a solution, but no luck. If have a column, say G, that has either H or D in it. I want to insert a blank line above any instance of H. I have tried the code that I could find, but if I have H in two consectutive rows, it does not insert the blank row. example below.

Column G
Before

H
D
D
H
H

After

H
D
D

H

H



Please let me know what additional info you may need. Thank you inadvance for any help.