The 19-year-old Fulham striker will stay on loan at Dundee United until 16th January.
“Lauri is a player I have been aware of for some time, having seen him play at Liverpool,” manager Peter Houston told the club’s official website.
“Once I knew he was available and knowing how highly he is rated by Fulham’s reserve coach Billy McKinlay, I wanted him signed up quickly.
“This loan arrangement will provide the opportunity for him to further develop his potential at first-team level whilst adding a much-needed striking option to our first-team squad.
“He clearly has a big future ahead of him and it’s great that he knows he can enhance his development here at Tannadice.”