Your major sources should be the works of Jacques Lacan himself. Next, you might want to look at Lacanian Ink, a journal devoted to Lacan studies, and the works of his collaborator and biographer Jacques-Alain Miller and also Slavoj Žižek . Another major scholar in literary Lacan studies is Ellie Ragland Sullivan.
The main way to find peer reviewed articles on literary topics is to go into the electronic resource section of your university library catalogue. The MLA International Bibliography catalogue scholarly works on literary studies. Another major resource is Jstor, which contains back issues of scholarly journals in .pdf format. In both of these resources, simply do a full text search for 1984 and Lacan to pull up previous work on the topic.
Ressentiment, the Superego, and Totalitarianism: George Orwell's 1984
S Cheng - Cardozo L. Rev., 2002 - HeinOnline