After the establishment of the royal dictatorship of King Alexander I of Yugoslavia, Lončar withdrew from politics, dedicating himself to his scholarly and editorial work.
He died in Ljubljana and was buried in the Žale cemetery.
Major works
Politično življenje Slovencev (Political Life of Slovenes, 1906)
Dr. Janez Bleiweis in njegova doba (Dr. Janez Bleiweis and His Epoch, 1910)
Slovenci: načrt slovenske socialne zgodovine (Slovenes: A Sketch of Slovene Social History, 1911)
Janko Kersnik, njega delo in doba (Janko Kersnik: His Work and Epoch, 1914)
Politika in zgodovina : nekoliko odgovorov na dnevna vprašanja (Politics and History: Some Answers to Current Questions, 1923)
Kako je nastalo današnje delavstvo in njegovo gibanje (The Genesis of the Modern Working Class and Its Political Movement, 1930)
Dragotin Dežman in slovenstvo (Dragotin Dežman and the Slovene Identity, 1930)
The Slovenes: A Social History from the Earliest Times to 1910 (1940)
References
^Savnik, Roman (1971). Krajevni leksikon Slovenije, vol. 2. Ljubljana: Državna založba Slovenije. p. 94.
^Taufbuch. Brdo. 1862–1886. p. 34. Retrieved November 10, 2022.{{cite book}}: CS1 maint: location missing publisher (link)