You can use an ifs statement to suppress a blank line. Please see below for more information about ifs statements:
ifs(condition A, then do this, otherwise do this)
ifs(Telephone="","",Telephone & "<br>")
If the Telephone field is blank, then put nothing, otherwise put the contents of the Telephone field followed by a line break.
Some options for the condition in the ifs statements:
a. If the field is not blank
This means if the Extension field is not blank, then insert “ext”, otherwise put nothing.
b. If the field contains a certain value
ifs(Telephone="Chicago", "773 555-5555", "")
This means if the Telephone field contains Chicago, then insert 773 555-5555, otherwise put nothing.
c. If the field is blank
ifs(Extension="","", "EXT." & Extension)
This means if the Extension field is blank, then put nothing, otherwise insert EXT. followed by the contents of the Extension field.