This title form looks similar to the artist naming with a nickname like GivenName "Niackname" FamilyName (For Japanese, 苗字"nick"名前).
古書堂ノスタルジヰ (Old Bookstore 'NOSTALGIE') → 古書"ノスタルジヰ"堂 (Old Book "NOSTALGIE" Store)
Nostalgie for ノスタルジヰ[nosutarujii] is from the website link (nakae-mitsuki.net/nostalgie/).
English title ANTIQUARIAN NOSTALGIA is from the additional jacket (event-only ver) and the website.
＝＝＝＝
edit:
Tr.3 哂ふ is pronounced as Warau, not Warafu.
It seems to be an archaic writing for 哂う.
http://www5a.biglobe.ne.jp/accent/kana/kana0.htm