
Max M. answered 04/19/19
Harvard Literature major with 20 years of coaching writers
There are a lot of potential answers, but here are a few big points to look at.
Oranges and Lemons is a children's song, basically a nursery rhyme, and one that Orwell's audience would know, and would probably teach to their children. Orwell wrote this in 1949, and it's set in--surprise, surprise--1984, so how far into the future is that, and how old would you guess Winston is? What I'm getting at is: Winston didn't learn the song from a history book or something, he grew up knowing it. A lot of dystopian sci-fi is set in the far-off future, where the world of the author's present has long since vanished, like The Hunger Games. This is set in a future that has living memory of the present. What does that tell you about how quickly this world came into being? Why would Orwell make that choice? To give you some context, a lot of sci-fi since then has taken a cue from Orwell, like the first couple of Terminator movies, V for Vendetta, and Handmaid's Tale, to pick just three. Winston is living in this unrecognizable world, but he has dim memories of a recognizable one, in the form of a children's song he used to know. While we're on the subject, what does it mean that his memory is so dim? What does it mean when he starts remembering more of it?
Also, it's a song about churchbells. IngSoc, the authority in 1984, is fiercely atheistic--they accept no higher power than them, no code of morality that they don't control, and no private sense of goodness or virtue. In that context, what would happen if you let people sing songs about churches?
And that last line. It's interesting, isn't it, how many children's songs are about violence, death and disaster, and we don't even notice. "London Bridge is falling down..." "...ashes, ashes, we all fall down," "...who cut off their tails with a carving knife..." You can probably think of more yourself. If it's just kindergartners dancing in a circle, it's all pretty innocent, right, but how does it change if a coldly violent government official reminds you of it while you're under arrest for singing children's songs?