How do create a hyperlink using a formula?

Cell A = http://www.jira.com/

Cell B = P1-123

Cell C = Cell A & Cell B = http://www.jira.com/P1-123 = great!

However, then, I copy the formula down and this happens:

Cell A = http://www.jira.com/

Cell B = P1-124

Cell C = Cell A & Cell B = http://www.jira.com/P1-124 = BUT - when I click edit hyperlink it shows P1-123 - is there a way to adjust the formula or equivalent so that is shows a link to http://www.jira.com/P1-124 instead of http://www.jira.com/P1-123??

In short, it displays at http://www.jira.com/P1-124 but when clicked goes to http://www.jira.com/P1-123.

Is there a way to solve this without VBA?

My current formula is:

=IF(C7<>"","https://www.jira.com/"&C7,"")